GB1594708A - Tensioning device for pliable elements - Google Patents

Description

(54) A TENSIONING DEVICE FOR PLIABLE ELEMENTS (71) We, SEASAFETRANSPORTAB, a Swedish company of Olaus Petrigatan 10, 115 34 Stockholm, Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a tensioning device for pliable elements such as chains, ropes or cables.

It is an object of this invention to provide an improved tensioning device for such pliable elements. According to the present invention a tensioning device for pliable elements comprises an elongated hollow first support member having openings in the opposed axial ends thereof, a first connecting device secured to said first support member for engagement by a link, eyelet or hook of said pliable element, a second support member located slidably within said first support member, a second connecting device secured to said second support member for engagement by a link, eyelet or hook of said pliable element spaced from the link, eyelet or hook engageable by said first connecting device and projecting through the opening in one end of the first support member, a screw-threaded member extending axially within the first support member and arranged to co-operate with screw-threads on the second support member, one end of the screw-threaded member projecting through the opening in the other end of the first support member and being arranged for engagement by drive means for rotation of the screw-threaded member whereby to produce relative axial displacement between the first and second support members, the first and second connecting devices being so shaped and/or so located on their respective support members that with the respective links, eyelets or hooks of said pliable element engaging said first and second connecting devices and said pliable element extending lengthwise therefrom in a common direction, the said one end of the screw-threaded member is spaced from said pliable element a sufficient distance to permit operation of the drive means without impediment from the pliable element.

The first connecting device may be laterally offset from the longitudinal axis of the screw-threaded member, so that an imaginary line through the points of engagement between the connecting devices and the links, eyelets or hooks of the pliable element is inclined to the longitudinal axis of the screw-threaded member.

Alternatively, the first connecting device may comprise a member having two ends respectively secured to two positions on the first support member which are symmetrically disposed on opposite sides of the longitudinal axis of the screw-threaded member. This latter form of first connecting device may comprise a U-shaped member the two free ends of which are respectively secured to opposite sides of the first support member.

Three tensioning devices embodying the invention are hereinafter described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view, partly in phantom of à first tensioning device with a sliding housing and a guide-piece of cylindrical form, including a transverse cross-section of the casting on the line A-A; Figure 2 is a view, similar to Figure 1, of a second tensioning device with a sliding housing and a guide-piece of rectangular form; and Figure 3 is a view, similar to Figure 1 and Figure 2, of a third tensioning device with a sliding housing and a guide-piece of rectangular form with a connecting device on the housing in the form of a U-shaped arc.

Referring to the drawings, Figure 1 shows a tensioning device which is cylindrical. The tensioning device consists of a cylindrical guide-piece 1 which has an eyelet connecting device 3 for connection to a pliable element, for example, a chain 14. At the end of the guide-piece 1 remote from the connecting device 3 the tensioning device is welded to a nut 10. Over the guide-piece 1 is fitted a sliding piece in the form of a housing 8, in the top of which is journalled a screw 5 which is screwed into the nut 10 of the guide-piece 1. At the top of the housing 8, the screw 5 emerges in the form of a parallelepipedic driving head 11 intended to be driven by a driver chuck 19 of a motor unit 1/ which may be pneumatlcally or electrically driven from a feeder line 18.

Close to the top of the housing 8 is an eyelet connecting device 7 in the form of a hook. This is so shaped that the line joining the point of engagement of the eyelet of the upper (as viewed) part of the chain 14 and the point of engagement for the eyelet of the lower part (as viewed) of the chain 14 in the connecting device 3 forms a relatively large angle with the longitudinal centre line of the screw 5.

A relatively large space is thus provided for coupling the driver chuck 19 of the motor unit 17 to the driving head 11. lye essentially semicircular shape of the eyelet connecting device 3 contributes to the inclination of the tensioning device in relation to the general direction of pull of the chains 14.

The tensioning device shown in Figure 2 is largely similar to that of Figure 1 and like parts are identified by like numerals. The only difference is that the cross-section along line B-B is rectangular. This provides that the two connecting devices 3 and 7 will lie in a common plane through the centre line of the screw. Furthermore the manufacture of this embodiment will be somewhat simpler and therefore cheaper than that shown in Figure 1.

The tensioning device shown in Figure 3 is very similar to that shown in Figure 2. The one shown in Figure 3 differs in that the sliding housing 8 has an eyelet connecting device 7 symmetrically fitted to its top. The device 7 is formed as a U-shaped arc which is so high and so wide that it accommodates the motor unit 17 when the latter's driver chuck 19 is to be brought into engagement with the driving head 11 of the tensioning device.

This embodiment, which is usable for very large tensioning device units, allows the tensioning device to be fitted exactly in the direction of pull of the chain 14.

WHAT WE CLAIM IS: 1. A tensioning device for pliable elements comprising an elongate hollow first support member having openings in the opposed axial ends thereof, a first connecting device secured to said first support member for engagement by a link, eyelet or hook of said pliable element, a second support member located slidably within said first support member, a second connecting device secured to said second support member for engagement by a link, eyelet or hook of said pliable element spaced from the link eyelet or hook engageable by said first connecting device and projecting through the opening in one end of the first support member, a screw-threaded member extending axially within the first support member and arranged to co-operate with screw threads on the second support member, one end of the screw-threaded member projecting through the opening in the other end of the first support member and being arranged for engagement by drive means for rotation of the screw-threaded member whereby to produce relative axial displacement between the first and second support members, the first and second connecting devices being so shaped and/or so located on their respective support members that with the respective links, eyelets or hooks of said pliable element engaging said first and second connecting devices and said pliable element extending lengthwise therefrom in a common direction, the said one end of the screw-threaded member is spaced from said pliable element a sufficient distance to permit operation of the drive means without imipediment from the pliable element.

2. A tensioning device as claimed in Claim 1, wherein the first connecting device is laterally offset from the longitudinal axis of the screw-threaded member, so that an imaginary line through the points of engagement Between the connecting aevlces and the links, eyelets or hooks of the pliable element is inclined to the longitudinal axis of the screw-threaded member.

3. A tensioning device as claimed in Claim 1, wherein the first connecting device comprises a member having two ends respectively secured to two positions on the first support memDer wmcn ait: SyllllllC;LII- cally disposed on opposite sides of the lon gitudinal axis of the screw-threaded member.

4. A tensioning device as claimed in Claim 3, wherein the first connecting device is a U-shaped member the two free ends of which are respectively secured to opposite sides of the first support member.

5. A tensioning device as claimed in any preceding claim, wherein the first and second support members are substantially cylindrical.

6. A tensioning device as claimed in Claim 5, wherein the first and second support members are substantially circular in crosssection.

7. A tensioning device as claimed in Claim 5, wherein the first and second support members are substantially rectangular in cross-section.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. the top of which is journalled a screw 5 which is screwed into the nut 10 of the guide-piece 1. At the top of the housing 8, the screw 5 emerges in the form of a parallelepipedic driving head 11 intended to be driven by a driver chuck 19 of a motor unit 1/ which may be pneumatlcally or electrically driven from a feeder line 18. Close to the top of the housing 8 is an eyelet connecting device 7 in the form of a hook. This is so shaped that the line joining the point of engagement of the eyelet of the upper (as viewed) part of the chain 14 and the point of engagement for the eyelet of the lower part (as viewed) of the chain 14 in the connecting device 3 forms a relatively large angle with the longitudinal centre line of the screw 5. A relatively large space is thus provided for coupling the driver chuck 19 of the motor unit 17 to the driving head 11. lye essentially semicircular shape of the eyelet connecting device 3 contributes to the inclination of the tensioning device in relation to the general direction of pull of the chains 14. The tensioning device shown in Figure 2 is largely similar to that of Figure 1 and like parts are identified by like numerals. The only difference is that the cross-section along line B-B is rectangular. This provides that the two connecting devices 3 and 7 will lie in a common plane through the centre line of the screw. Furthermore the manufacture of this embodiment will be somewhat simpler and therefore cheaper than that shown in Figure 1. The tensioning device shown in Figure 3 is very similar to that shown in Figure 2. The one shown in Figure 3 differs in that the sliding housing 8 has an eyelet connecting device 7 symmetrically fitted to its top. The device 7 is formed as a U-shaped arc which is so high and so wide that it accommodates the motor unit 17 when the latter's driver chuck 19 is to be brought into engagement with the driving head 11 of the tensioning device. This embodiment, which is usable for very large tensioning device units, allows the tensioning device to be fitted exactly in the direction of pull of the chain 14. WHAT WE CLAIM IS:

1. A tensioning device for pliable elements comprising an elongate hollow first support member having openings in the opposed axial ends thereof, a first connecting device secured to said first support member for engagement by a link, eyelet or hook of said pliable element, a second support member located slidably within said first support member, a second connecting device secured to said second support member for engagement by a link, eyelet or hook of said pliable element spaced from the link eyelet or hook engageable by said first connecting device and projecting through the opening in one end of the first support member, a screw-threaded member extending axially within the first support member and arranged to co-operate with screw threads on the second support member, one end of the screw-threaded member projecting through the opening in the other end of the first support member and being arranged for engagement by drive means for rotation of the screw-threaded member whereby to produce relative axial displacement between the first and second support members, the first and second connecting devices being so shaped and/or so located on their respective support members that with the respective links, eyelets or hooks of said pliable element engaging said first and second connecting devices and said pliable element extending lengthwise therefrom in a common direction, the said one end of the screw-threaded member is spaced from said pliable element a sufficient distance to permit operation of the drive means without imipediment from the pliable element.

2. A tensioning device as claimed in Claim 1, wherein the first connecting device is laterally offset from the longitudinal axis of the screw-threaded member, so that an imaginary line through the points of engagement Between the connecting aevlces and the links, eyelets or hooks of the pliable element is inclined to the longitudinal axis of the screw-threaded member.

3. A tensioning device as claimed in Claim 1, wherein the first connecting device comprises a member having two ends respectively secured to two positions on the first support memDer wmcn ait: SyllllllC;LII- cally disposed on opposite sides of the lon gitudinal axis of the screw-threaded member.

4. A tensioning device as claimed in Claim 3, wherein the first connecting device is a U-shaped member the two free ends of which are respectively secured to opposite sides of the first support member.

5. A tensioning device as claimed in any preceding claim, wherein the first and second support members are substantially cylindrical.

6. A tensioning device as claimed in Claim 5, wherein the first and second support members are substantially circular in crosssection.

7. A tensioning device as claimed in Claim 5, wherein the first and second support members are substantially rectangular in cross-section.

8. A tensioning device for pliable ele

ments substantially as hereinbefore described with reference to Figure 1, Figure 2 or Figure 3 of the accompanying drawing.